The invention relates to a method of manufacturing a stripe filter for optical usages, in particular in the television cameras.
The stripe filter has a transparent colorless plate such as a glass plate which is covered with fine parallel or crossed stripes assuming different colors. The stripes are about 10 .mu.m wide or wider, and are arranged regularly as to their colors. Therefore, a transparent film formed from a hardenable composition on the surface of the plate has been repeatedly subjected to a partially dyeing treatment to constitute the regularly arranged stripes.
In case that the whole area of the film is dyed at once, a partially decolorizing treatment has been repeatedly carried out. In these conventional methods, protecting layers having a predetermined pattern of slots must be formed each time of said partially dyeing or partially decolorizing for the purpose of preventing the dye or decolorizer from acting on the undesirable zones of the film. The necessity of such protecting layer has made the manufacture of stripe filter much complicated, and said layer was not sufficiently effective to avoid contamination of the side portions of the stripes already dyed. Thus, there have been various difficulties in the control of dyeing processes, the selection of dyestuffs and the assurance of exactitude in the quality of products. There was a possibility that the residual amount of the above-mentioned decolorizer, when used, and the decomposed dyestuff should change the spectra of fine colored stripes in course of time. In addition, it was an another serious drawback that the portions of said transparent film were apt to be dyed to uneven depth or richness of color.